Dry film photosensitive resist

ABSTRACT

A dry film photosensitive resist, according to the invention, is a flexible laminated structure consisting of three layers of which the first is a transparent polymer film transmitting UV radiation and having a thickness of 5-100μ; the second of said layers being a light-sensitive layer having a thickness of 5-1,000μ and comprising a combination of a carboxyl-containing polymer-thickener, a polar oligomer, and a monomeric substance having a boiling point above 200° C. at 760 mm Hg; the third of the layers being a film from a polymeric substance having a thickness of 5-100μ, the last-mentioned layer being a protective layer for the light sensitive layer and being disposed thereon. All the three layers are adhesively bonded together. The light-sensitive layer contains as the carboxyl-containing polymer thickener, a water insoluble copolymer of a monomer or a mixture of monomers having a neutral reaction with the carboxyl-containing monomer.

This is a continuation of application Ser. No. 822,569, filed Aug. 8,1977, now abandoned.

The present invention relates to compositions of light-sensitive polymermaterials used for printed circuitry, and more particularly to dry filmphotosensitive resists.

Dry film photosensitive resists can be used for manufacturing conductorsof printed circuit boards, printed windings, scales, grids, and otheritems by the photochemical method.

BACKGROUND OF THE INVENTION

Known in the art are dry film photosensitive resists which are aflexible laminated structure consisting of three layers of which thefirst is a transparent polymer film transmitting UV radiation and havinga thickness of 5-100μ; the second of said layers is a light-sensitivelayer having a thickness of 5-1,000μ and comprising a combination of acarboxyl-containing polymer-thickener, a polar oligomer, and a monomericsubstance having a boiling point above 200° C. at 760 mm Hg; the thirdof the layers is a film from a polymeric substance having a thickness of5-100μ and being protective for said light-sensitive layer and disposedthereon.

In one of the known dry film photosensitive resists a light-sensitivelayer contains as a carboxyl-containing polymer-thickener a waterinsoluble copolymer of methylmethacrylate with 10 mol.% of methacrylicacid, as a monomeric substance and a polar oligomer pentaerythritoltriacrylate is used. The light-sensitive layer also contains additivesof photoinitiators of radical polymerization or a mixture thereof,inhibitors of radical thermopolymerization, dyes, and placticizers.

The use of pentaerythritol triacrylate in combination with theabove-cited polymer-thickener makes it possible to obtain dry filmphotosensitive resists possessing a satisfactory spectrum of propertiesincluding stability in galvanic electrolytes.

However, qualitative development of such dry film photosensitive resistsis impossible when aqueous developers are used containing no organicsubstances. For developing the above-cited photosensitive resists,considerable amounts (up to 10 vol.% and more) of organic solvents areusually introduced into the developer, such as butyl cellosolve, as wellas surfactants, usually non-ionogenic.

Organic substances contained in the developer are rather difficult toremove from the spent developer; therefore, when the above-cited dryfilm photosensitive resists are used, environmental contamination takesplace, which, under the conditions of mass production, may present aserious ecological problem.

The development of dry film photosensitive resists with aqueoussolutions containing no organic substances becomes possible when theacidity of the carboxyl-containing polymer-thickener is increased. Forexample, if a copolymer of methylmethacrylate with 35 mol.% methacrylicacid is used as a polymer-thickener and pentaerythritol triacrylate as amonomeric substance, the light-sensitive layer is well developed with a1% aqueous solution of sodium carbonate without the addition of organicsolvents. But in this case the chemical stability of the photosensitiveresist decreases considerably.

When pentaerythritol triacrylate is replaced by less hydrophilic and,consequently, more stable in aggressive media, monomeric substances,such as pentaerythritol tetraacrylate or trimethylolpropanetrimethylacrylate, the chemical stability of the photosensitive resistcan be increased. However, this is accompanied by deterioration of thecompatibility of the light-sensitive layer components and by instabilityof adhesion of the light-sensitive layer to the substrate, where thephotosensitive resist is applied, especially after prolonged storage.

Thus, because of the above-mentioned disadvantages, the field ofapplication of the known dry film photosensitive resists is limited.

BRIEF DESCRIPTION OF THE INVENTION

It is an object of the invention to provide such a composition of a dryfilm photosensitive resist, which will make it possible to develop saidphotosensitive resist with aqueous solutions of weak alkalies withoutthe addition of organic substances and to ensure its high stability inacidic media.

Said object is accomplished by the provision of a dry filmphotosensitive resist which is a flexible laminated structure consistingof three layers of which the first is a transparent polymer filmtransmitting UV radiation and having a thickness of 5-100μ; the secondof said layers being a light-sensitive layer having a thickness of5-1,000μ and comprising a combination of a carboxyl-containingpolymer-thickener, a polar oligomer, and a monomeric substance having aboiling point above 200° C. at 760 mg Hg; the third of said layers beinga film from a polymeric substance having a thickness of 5-100μ, thelast-mentioned layer being a protective layer for said light-sensitivelayer and being disposed thereon, all the three said layers being waterinsoluble copolymer of a monomer or a mixture of monomers having aneutral reaction with the carboxyl-containing monomer, the content ofthe carboxyl-containing monomer in the copolymer ranging from 20 to 50mol.%. The polar oligomer in said light-sensitive layer is ahydroxylcontaining compound obtained through chemical addition of anorganic acid to epoxy resins or mixtures thereof and having a chainlength of from 300 to 3,000 carbon units. The monomeric substance insaid light-sensitive layer is a fully substituted ester of a polyatomicalcohol with carboxylic acids, at least two hydroxyl groups of thepolyatomic alcohol being substituted by residues of acrylic and/ormethacrylic acids; the weight ratio of said polymer-thickener, polaroligomer, and monomeric substance being 100:15-100:15-100 respectively.

It is recommended to use a photosensitive resist wherein thelight-sensitive layer contains as a carboxyl-containingpolymer-thickener a water insoluble copolymer of 50 mol.% of styrenewith 50 mol.% of monoisobutyl ester of fumaric acid, and as a polaroligomer said light-sensitive layer contains a hydroxyl-containingcompound obtained through chemical addition of methacrylic and/oracrylic acids to an epoxy resin. It is desirable that as a monomericsubstance the light-sensitive layer should contain1,1,1-trimethylpropane triacrylate.

To increase light sensitivity, the light-sensitive layer of theherein-proposed dry film photosensitive resist may containphotoinitiators of radical polymerization, the content of saidinitiators being from 2 to 20% by weight of the carboxyl-containingpolymer-thickener.

Aromatic ketones, aromatic diketones, said multi-nucleous quinones canbe used as photoinitiators of radical polymerization.

For enhancing plasticity and reducing brittleness, the light-sensitivelayer may contain a plasticizer in the amount of from 5 to 25% by weightof the light-sensitive layer.

Dibutylphthalate, glycerol triacetate, and trimethylolpropane triacetatecan be used as a plasticizer.

To increase the duration of storage of the dry film photosensitiveresist, inhibitors of radical polymerization may be included into thecomposition of the light-sensitive layer in the amount of 0.01 to 5.0%by weight of the carboxylcontaining polymer-thickener. For example, asinhibitors of radical polymerization use can be made of phenols, namely,hydroquinone or para-methoxyphenol. For contrast dyeing of thelight-sensitive layer, the latter may contain dyeing substances inamounts of from 0.1 to 5.0% by weight of carboxyl-containingpolymer-thickener. As dyeing substances use should be made oftriphenylmethane dyes, namely, "Methylviolet", "Crystalline violet", and"Rhodamin ".

The herein-proposed dry film photosensitive resist contains as the firstlayer preferably a film from polyethylene terephthalate and as the thirdprotective layer preferably a film from polyethylene.

DETAILED DESCRIPTION OF THE INVENTION

According to the invention, the dry film photosensitive resist isprepared in the following way.

A 20-40% solution of a light-sensitive layer comprising acarboxyl-containing polymer-thickener, a polar oligomer, and a mononericsubstance in a highly volatile solvent is applied by way of uniformspraying through a spinneret to a transparent polymer film (substrate)having a thickness of 5-100μ and transmitting UV radiation in the regionof 300-400 nm, for example, polyethylene terephthalate film.

As a carboxyl-containing polymer-thickener use is made of waterinsoluble copolymers obtained by polymerization of two or more monomers,one of which is an unsaturated acid, for example, acrylic, methacrylic,maleic, fumaric, itaconic, or an acid monoester of an unsaturated acid,for example, monoisoamyl ester of maleic acid. The second monomer iswater insoluble, i.e. its solubility in water at 20° C. does not exceed3 weight % and pH is approximately equal to 7. The second monomer canbe, for example, alkylmethacrylates and alkylacrylates containing from 1to 10 carbon atoms in an alcohol radical; styrene and its derivativescapable of copolymerizing which are substituted in α-position or in thearomatic ring; esters of vinyl alcohol, for example, vinyl acetate orvinylpropionate; ethers of vinyl alcohol, for example, vinyl-n-butylether; sterically hindered monomers incapable of homopolymerization,such as stilbene; dienes capable of copolymerization with the formationof soluble copolymers such as butadiene or diallyl phthalate. Inaddition, the second monomer can consist of the above-cited waterinsoluble monomers in a mixture with water soluble monomers such asmethacrylamide, acrylamide or a mixture thereof, monomethacrylate, andethyleneglycol monoacrylate (the content of water soluble monomer in themixture should be relatively small--no more than 20 mol.%).

It is preferable to use water insoluble copolymers with a molecularweight from 2 to 200 thousand conventional units. Water insolublecopolymers, in case of their mutual compatibility in the presence of theother components of the light-sensitive layer, may enter into thecomposition of the dry film photosensitive resist as a mixture.

As a polar oligomer, hydroxyl-containing compounds are used, obtainedthrough chemical addition of organic acids to epoxy resins or theirmixtures, said epoxy resins being characterized by a high hydroxylnumber (usually 4-8 weight % of OH-groups) and a minimum epoxy numberwhich is, as a rule, no more than 10% of the initial epoxy number of theepoxy resin being used. It is preferable that the epoxy number of thepolar oligomer be equal or close to zero.

Mono- and dicarboxylic acids having a molecular weight no higher than200 conventional units are usually used for obtaining a polar oligomer.The use of a mixture of organic acids is also possible. Unsaturatedacids or their monosubstituted derivatives are most widely applied forproducing a polar oligomer. Among them are acrylic, methacrylic,α-halogen acrylic, maleic, fumaric, or itaconic acid. Dibasic carboxylicacids can be used in the form of anhydrides if their interaction withepoxy resins does not yield insoluble products with a three-dimensionalstructure and if the epoxy number of the obtained oligomer does not dropbelow 3 weight % of the OH-groups.

Epoxy resins for producing a polar oligomer may have initial content ofthe epoxy groups ##STR1## (I) from 3 to 40 weight %; the molecule ofepoxy resin may have from 1 to 10 epoxy groups in the form of glycideresidue ##STR2## The initial epoxy resins can be liquid, viscous-fluidor solid, depending on their molecular weight and structure. Solid epoxyresins are amorphous or crystallizing substances.

Initial epoxy resins can be obtained by direct epoxidation ofunsaturated compounds, for example, low-molecular polybutadiene,vinylcyclohexane, and peroxide compounds, or by condensation oflow-molecular epoxy compounds, such as epichorohydrin, with compoundshaving mobile atoms in the molecule: phenols (for example,4,4-dihydroxy-2,2-diphenylpropane, hydroquinone, pyrogallol; aliphaticpolyatomic alcohols (pentaerythritol, trimethylol propane, andethyleneglycol); amines (aniline, metaphenylene diamine); dicarboxylicacids (phthalic, adipic, or maleic); cyanuric acid; and phenolformaldehyde resins. It is also possible to apply mixed epoxy resinsobtained, for example, by joined condensation of two differentbisphenols, as well as modified epoxy resins obtained by inter-action oflow-molecular di- and polyepoxy products with compounds containingmobile atoms, for example, phenols.

To obtain a polar oligomer, it is most preferable to use epoxy resins onthe base of 4,4'-dioxy-2,2-diphenyl propane (bisphenol A).

A polar oligomer can be obtained by catalytic addition of organic acidsto the above-cited epoxy resins in the presence of weak bases and/orupon heating of the reaction mixture up to 80°-200° C.

As a monomeric substance entering into the composition of thelight-sensitive layer use is made of fully substituted esters ofpolyatomic alcohols. This means that these monomers do not contain freehydroxyl and carboxyl groups which may be present as slight impuritiesonly. It is very important that the monomer molecule contain at leasttwo ester groups of acrylic and/or methacrylic acids.

For example, suitable are the following compounds: trimethylol propanetrimethacrylate; trimethylolpropane triacrylate; pentaerythritoltetramethacrylate; pentaerythritol diacetate dimethacrylate;pentaerythritol diacetate diacrylate; triethyleneglocyl acrylatemethacrylate; dimethacrylate (bis-ethyleneglycol)-phthalate;diacrylate(bis-ethyleneglycol)-phthalate;tetramethacrylate(bis-trimethylolpropane)-succinate;tetracrylate(bis-trimethylolpropane)-succinate.

For increasing light sensitivity, the herein-proposed dry filmphotosensitive resist may contain photoinitiators of radicalpolymerization, for example, aromatic ketones or multinucleous quinones:benzophenone, Michler ketone, dibenzoyl, benzoine methylate,2-tert-butyl anthraquinone, or mixtures thereof. A photoinitiator isintroduced usually in an amount of 2-20% by weight of thecarboxyl-containing polymer-thickener. Photoinitiators or their mixturesmay be introduced into the light-sensitive layer either as individualcompounds or as chemically bonded with one of the components of thelight-sensitive layer. It is possible to use photoinitiators incombination with activators (acceleraters) of radicalphotopolymerization, for example, N-phenyl glycine, the content ofactivators being usually 0.5-5.0% by weight of the carboxyl-containingpolymer-thickener.

Enhanced plasticity and reduced brittleness of the irradiatedlight-sensitive layer are attained by introduction into the compositionof the light-sensitive layer plasticizers such as dialkyl (C₁ -C₁₀)esters of dicarboxylic acids, esters of polyatomic alcohols, and thelike (for instance, dibutyl phthalate, glycerol triacetate,glycerol-1,3-diacetate, trimethylolpropane triacetate). A plasticizer isusually added in an amount of from 5 to 25% by weight of thelight-sensitive layer.

For increasing the duration of storage of the dry film photosensitiveresist, the light-sensitive layer may contain inhibitors of radicalpolymerization, such as phenols, namely, hydroquinones,para-methoxyphenol, para-tert-butylphenol formaldehyde resin in anamount of 0.01-5.0% by weight of the carboxyl-containingpolymer-thickener.

To make the light-sensitive layer contrast and perfectly visible forvisual quality control of the items obtained with the use of the dryfilm photosensitive resist, the layer should contain dyeing substancessuch as triphenylmethane dyes: "Methyl violet", "Crystalline violet" andothers, or finely dispersed pigments in an amount of 0.1-5.0% by weightof the carboxyl-containing polymer-thickener.

After applying the light-sensitive layer to the substrate, it is driedby flowing with air at 20°-150° C. for 0.5-5 minutes. Then, a protectivelayer having a thickness of 5-100μ, for instance, a polyethylene film,is applied to the light-sensitive layer with the aid of a roller coveredwith rubber. After that the resultant dry film photosensitive resist isrolled into a reel (600 mm in width and up to 300 m long).

Owing to the above-cited combination of components of thelight-sensitive layer, the herein-proposed dry film photosensitiveresist can be developed with aqueous solutions of weak alkalies, such ascarbonates, bicarbonates, and silicates of alkali metals, without theaddition of any organic substance into the developer. Sufficiently highchemical stability of the photosensitive resist makes it fit for usewhen manufacturing items of printed circuitry both by the negative andpositive combined method. Thus, the chemical stability of the proposedphotosensitive resist is sufficient for etching copper foil with ferricchloride solution to the depth of 100μ and over; for galvanicprecipitation of copper from a sulphate electrolyte during 1 hour andmore with subsequent galvanic covering by a tin-lead alloy from afluoboric electrolyte during 1 hour or more. After performingphotolitographic operations, a protective relief based on the proposeddry film photosensitive resist can easily be removed from the surface ofthe item by 5-20% aqueous solution of alkalies (NaOH, KOH, etc.).

The spent solutions of the developer and of the removing agent areneutralized with inorganic acids. The components of the light-sensitivelayer of the photosensitive resist can be isolated from the aqueousphase.

The proposed photosensitive resist can be used on conventional equipmentwhich is employed for mechanized treatment of the known dry filmphotosensitive resists.

For a better understanding of the present invention specific examples ofpreparing the proposed dry film photosensitive resist are givenhereinbelow by way of illustration.

EXAMPLE 1

A light-sensitive layer 35μ in thickness is applied to a polyethyleneterephthalate film (a substrate) by way of uniform coating thereofthrough a spinneret. The composition of the light-sensitive layer is asfollows (in weight parts):

copolymer of styrene with monoisobutyl ester of fumaric acid (50:50mol.%)--100.0;

product of addition of methacrylic acid to an epoxy resin based on4,4'-di-hydroxy-2,2-diphenylpropane (molecular weight of the product is600 conventional units, acidic number is 2 mg KOH/g; content of residualepoxy groups is 0.4 weight %)--50.0;

dimethacrylate(bis-ethyleneglycol)-phthalate--50.0.

The coating is performed from a solution of the components in anacetone-isopropanol mixture having a viscosity of 18 sec by viscosimeterat 20° C.

The light-sensitive layer is dried by blowing with air at 50° C. for 10minutes, after which a protective polyethylene layer 20μ thick isapplied to the light-sensitive layer with the aid of a roller coveredwith a rubber layer. The three-layer system is rolled into a reel.

The obtained dry film photosensitive resist is applied, after removingthe protective layer, to the surface of copper foil purified from oxidesand fat impurities; the application is performed with the help of astandard roller laminator, the temperature of its heating elements being115°±3° C.

An arrangement equipped with 1 kW mercury high-pressure lamps is usedfor the exposure of the sample. The time of the exposure through a filmphotographic mask is 40 min. During the exposure the sample isintensively cooled with air to avoid thermal polymerization of thelight-sensitive layer.

After the exposure, the polyethylene terephthalate film is removedstripped off from the light-sensitive layer and the sample is developedon a jet apparatus with a 2% aqueous solution of sodium carbonate for 1minute.

The protective relief thus obtained is stable in a sulphate electrolytefor galvanic precipitation of copper and in a fluoroborate electrolytefor galvanic precipitation of tin-lead alloy (60 minutes of exposure ineach electrolyte under conditions of subsequent galvanic covering).

After the galvanic covering has been performed, the protective layer canbe removed with a 10% aqueous solution of KOH.

EXAMPLE 2

A dry film photosensitive resist is obtained by following the proceduredescribed in Example 1 and then a light-sensitive layer is applied to apolyethylene film. After that a polyethylene terephthalate film isapplied to the light-sensitive layer with the aid of a roller coveredwith a rubber layer.

The dry film photosensitive resist obtained has the properties similarto those described in Example 1.

EXAMPLE 3

A dry film photosensitive resist is obtained and treated by followingthe procedure described in Example 1, but 10 weight parts of aphotoinitiator (benzoine ethylate) are introduced into the compositionof the light-sensitive layer.

For exposure of the sample, an arrangement is used equipped with 1 kWmercury high-pressure lamps. The time of the exposure through a filmphotographic mask is 50 sec. During the exposure the sample is cooledintensively with air to avoid thermal polymerization of thelight-sensitive layer.

After the exposure the polyethylene terephthalate film is removed(stripped off) from the light-sensitive layer and the sample isdeveloped on a jet apparatus with a 2% aqueous solution of sodiumcarbonate for 1 minute.

The protective relief thus obtained is stable in a sulphate electrolyteused for galvanic precipitation of copper and in a fluoroborateelectrolyte used for galvanic precipitation of a tin-lead alloy (theexposure in each electrolyte is 60 minutes under the condition ofsubsequent galvanic covering).

EXAMPLE 4

A dry film photosensitive resist is obtained by following the proceduredescribed in Example 3, but 0.3 weight parts of "Methyl violet" dye areintroduced into the composition of the light-sensitive layer. Theproperties of the dry film photosensitive resist obtained are similar tothose described in Example 1, but the protective relief in this caseacquires contrast blue coloring perfectly visible against the backgroundof the copper foil.

EXAMPLE 5

A dry film photosensitive resist is obtained by following the proceduredescribed in Example 3, but 0.1 weight part of an inhibitor(hydroquinone) is introduced into the composition of the light-sensitivelayer. The sample is tested by following the procedure described inExample 1, but the exposure time is 70 sec. The properties of the dryfilm photosensitive resist are similar to those described in Example 1.The time of storage of the dry film photosensitive resist with theinhibitor introduced increases to 12 months at 20° C. without light.

EXAMPLE 6

A light-sensitive layer 20μ in thickness is applied to a polyethyleneterephthalate film 25μ thick by uniform coating through a spinneret. Thecomposition of the light-sensitive layer is as follows (in weightparts):

copolymer of normal butylmethacrylate, methacrylic acid, andmethacrylamide (molar ratio is 57:35:8 respectively)--100.0;

product of addition of acrylic acid to an epoxy resin based on4,4'-dihydroxy-2,2-diphenylpropane (chain length of the product is 800carbon units, acidic number is 4.6 mg KOH/g, the content of the residualepoxy groups is 0.35 weight %)--25.0;

trimethylol ethane triacrylate--50.0;

glycerol-1,3-dipropionate--10.0;

4-diethylaminobenzophenone--3.0;

fluorenone--6.0;

dye "Rhodamine "--0.5;

paramethoxyphenol--0.2.

The dry film photosensitive resist is prepared and applied by followingthe procedure described in Example 1, but as a protective film use ismade of a polyvinyl alcohol film having a thickness of 25μ. The exposuretime is 120 sec. After the exposure, the polyethylene terephthalate filmis removed from the light-sensitive layer and the sample is developed ona jet apparatus with a 1% aqueous solution of potassium carbonate during1 minute. The protective relief is red in color and stable towards thesame media as the protective relief obtained on the basis of the dryfilm photosensitive resist described in Example 1.

EXAMPLE 7

A dry film photosensitive resist is prepared by following the proceduredescribed in Example 6, but instead of trimethylol ethane triacrylateuse is made of 56.0 weight parts of pentaerythritol triacrylatemonoacetate.

The obtained dry film photosensitive resist is used as described inExample 1, but the exposure time is 108 sec and a 1.5% aqueous solutionof sodium metasilicate is used as developer.

EXAMPLE 8

A light-sensitive layer 10μ thick is applied to a polyethyleneterephthalate film 12μ thick by way of uniform coating through aspinneret. The composition of the light-sensitive layer is as follows(in weight parts):

copolymer of methylmethacrylate, n-butylacrylate and methacrylic acid(molar ratio is 60:8:32 respectively)--100.0;

product of interaction of acetic acid with an epoxy resin based on4,4'-dihydroxy-2,2-diphenylpropane (chair length of the product is 550carbon units; acidic number is 6.2 mg KOH/g; hydroxyl number is 5.9weight % of OH groups; content of the residual epoxy groups is 0.15weight %)--80.0;

trimethylolpropane triacrylate--75.0;

benzoine methylate--8.0;

dye "Basic blue K"--0.5;

para-tert-butylphenol formaldehyde resin--0.5.

The dry film photosensitive resist is prepared and used by following theprocedure described in Example 1, but the exposure time is 75 sec. Theprotective relief is blue. The properties of the dry film photosensitiveresist are similar to those described in Example 1.

EXAMPLE 9

A light-sensitive layer 50μ thick is applied to a polyethyleneterephthalate film 60μ thick by uniform coating through a spinneret. Thecomposition of the light-sensitive layer is as follows (in weightparts):

copolymer of methylmethacrylate, n-butylmethacrylate, and methacrylicacid (molar ratio 60:5:35 respectively)--100.0;

product of addition of maleic and methacrylic acids (molar ratio 1:4) toan epoxy resin based on 4,4'-dihydroxy-2,2-diphenylpropane (chain lengthof the product is 650 carbon units; acidic number 15 mg KOH/g; contentof the residual epoxy groups equals zero)--90.0;

triethyleneglycol dimethacrylate--75.0;

benzoine methylate--5.0;

dye "Basic blue K"--0.3;

hydroquinone

The dry film photosensitive resist is prepared and used by following theprocedure described in Example 1, but the exposure time is 150 sec. Theproperties of the dry film photosensitive resist obtained are similar tothose described in Example 1.

EXAMPLE 10

The preparation and treatment of the dry film photosensitive resist aresimilar to those described in Example 9, but triethyleneglycoldimethacrylate is replaced with 80 weight parts of trimethylolpropanetriacrylate. The test of the obtained dry film photosensitive resist andits properties are similar to those described in Example 1.

EXAMPLE 11

A dry film photosensitive resist is obtained and treated by followingthe procedure described in Example 9, but triethyleneglycoldimethacrylate is replaced with a mixture of 50.0 weight parts oftriethyleneglycol diacrylate and 28.5 weight parts ofdiacrylate(bis-ethyleneglycol)-phthalate. The test of the obtained dryfilm photosensitive resist and its properties are similar to thosedescribed in Example 1.

EXAMPLE 12

A dry film photosensitive resist is obtained and treated by followingthe procedure described in Example 9, but benzoine methylate is replacedwith a mixture of photoinitiators consisting of 2.0 weight parts of2-tert-butyl anthraquinone, 2.5 weight parts of Michler ketone, and 3.0weight parts of benzophenone. The content of hydroquinone issimultaneously reduced down to 0.3 weight parts. The test of the dryfilm photosensitive resist and its properties are similar to thosedescribed in Example 1, but the exposure time is 120 sec.

EXAMPLE 13

A dry film photosensitive resist is prepared and treated by followingthe procedure described in Example 9, but the product of addition ofmaleic and methacrylic acids to an epoxy resin based on4,4'-dihydroxy-2,2-diphenylpropane is replaced with a mixture of twocompounds, namely, polar oligomers A and B:

A. 20 weight parts of the product of addition of methacrylic acid to anepoxy-cyanuric resin which has been obtained by condensation of cyanuricacid with epichlorohydrin in the presence of a basic catalyst (NaOH).The molecular weight of the product is 750 carbon units, the content ofthe residual epoxy groups is 0.6 weight %, the acidic number 0.45 mgKOH/g.

B. 50 weight parts of the product of addition of acrylic acid to anepoxy resin based on 4,4'-dihydroxydiphenyloxide. The chain length ofthe product is 520 conventional units; the content of the residual epoxygroups is 0.43 weight %; the acidic number is 3.2 mg KOH/g.

The dry film photosensitive resist is tested by following the proceduredescribed in Example 1, but the exposure time is 180 sec. The propertiesof the dry film photosensitive resist are similar to those described inExample 1.

EXAMPLE 14

A dry film photosensitive resist is prepared by following the proceduredescribed in Example 1, but the sensitive layer is 20μ thick and has thefollowing composition in weight parts:

copolymer of methylmethacrylate with 35 mol.% of methacrylicacid--100.0;

product of addition of acrylic acid to an epoxy resin obtained bycondensation of ethyleneglycol with epichlorohydrine in the presence ofboron trifluoride with subsequent treatment with alkali (chain length ofthe product is 360 conventional units, the content of the residual epoxygroups is 0.65 weight %, the acidic number is 2.5 mg KOH/g)--20.0;

trimethylolpropane acetate diacrylate--70.0;

dimethylphthalate--5.0;

benzoine methylate--10.0.

dye "Rhodamine 6 "--0.65;

para-butoxyphenol--0.05.

The dry film photosensitive resist is obtained and tested by followingthe procedure described in Example 1. The exposure time is 40 sec. Theprotective relief is red in color and its galvanic stability is similarto that of the dry film photosensitive resist described in Example 1.

EXAMPLE 15

A dry film photosensitive resist is obtained and treated by followingthe procedure described in Example 1, but the light-sensitive layer hasthe following composition in weight parts:

copolymer of methylmethacrylate with 33 mol.% of methacrylicacid--100.0;

product of addition of itaconic acid to an epoxy resin based on4,4'-dihydroxy-2,2-diphenylpropane (molecular weight of the product is2,900 carbon units, the content of the residual epoxy groups equalszero; the acidic number is 40.1 mg KOH/)--15.0;

product of addition of methacrylic acid to an epoxy resin based on4,4'-dihydroxy-2,2-diphenylpropane (chain length of the product is 580conventional units, the content of the residual epoxy groups is 0.45weight %, the acidic number is 3.6 mg KOH/g)--45.0;

triethylene glycol dimethacrylate--85.0;

2-methoxyethyl ester of benzoine--10.0;

dye "Methylene blue"--0.2;

quinhydrone--0.01.

The light-sensitive layer is coated on a polyethylene terephthalate film12μ thick, dried, and protected with a polyethylene film 20μ thick. Thedry film photosensitive resist is used by following the proceduredescribed in Example 1. The exposure time is 54 seconds. 1% aqueoussolution of potassium carbonate is used as a developer. The protectiverelief is stable in the same media as described in Example 1.

EXAMPLE 16

A dry film photosensitive resist is obtained and treated by followingthe procedure described in Example 15, but triethyleneglycoldimethacrylate is replaced with a mixture of 35.0 weight parts oftriethyleneglycol diacrylate and 50.0 weight parts of trimethylolpropanetriacrylate.

The dry film photosensitive resist is tested by following the proceduredescribed in Example 1, but the exposure time is reduced down to 48 sec.The properties of the resist are similar to those described in Example1.

EXAMPLE 17

A dry film photosensitive resist is obtained and treated by followingthe procedure described in Example 15, but the content of methacrylicacid in the copolymer is increased up to 35 mol.% and 5.0 weight partsof a plasticizer (1,3-diacetyne) are introduced. The test is performedby following the procedure described in Example 1. The exposure time is50 sec. A 1% aqueous solution of sodium bicarbonate is used as adeveloper. The properties of the obtained dry film photosensitive resistare similar to those described in Example 1.

EXAMPLE 18

A dry film photosensitive resist is obtained and treated by followingthe procedure described in Example 1, but the light-sensitive layer hasthe following composition in weight parts:

copolymer of methylmethacrylate, methacrylic acid, and methacrylamide(the molar ratio is 65:20:15 respectively)--100.0;

product of addition of methacrylic acid to an epoxy resin based on4,4'-dihydroxy-2,2-diphenylpropane (chain length of the product is 580carbon units, the content of the residual epoxy group is 0.45 weight %,the acidic number is 3.6 mg KOH/g)--25.0;

triethyleneglycol diacrylate--25.0;

benzoine methylate--5.0;

dye "Methyl violet"--0.15

para-methoxyphenol--0.1.

The thickness of the dried light-sensitive layer is 25μ. The exposuretime is 80 sec. A 2% aqueous solution of sodium carbonate is used as adeveloper. The dry film photosensitive resist is stable in the samemedia as that described in Example 1.

EXAMPLE 19

A dry film photosensitive resist is obtained and treated by followingthe procedure described in Example 18, but triethyleneglycol diacrylateis replaced with 28.0 weight parts of trimethylolpropane diacrylatemonoacetate. A plasticizer (7.0 weight parts of triacetyne) is added.The exposure time is increased up to 1.5 min.

The sample is developed in a 1% aqueous solution of potassium carbonate.The dry film photosensitive resist is tested by following the proceduredescribed in Example 1. Its properties are similar to those described inExample 1.

EXAMPLE 20

A dry film photosensitive resist is obtained and treated by followingthe procedure described in Example, 18 but benzoine methylate isreplaced with 12.0 weight parts of 2-ethoxyethyl ester of benzoine.Light sensitivity of the photosensitive resist increases, which makes itpossible to reduce the exposure time down to 40 sec. The dry filmphotosensitive resist is treated by following the procedure described inExample 1; its properties are similar to those described in Example 1.

EXAMPLE 21

A dry film photosensitive resist is obtained and treated by followingthe procedure described in Example 1, but the light-sensitive layercomprises the following components in weight parts:

copolymer of methylmethacrylate with methacrylic acid (32 mol.% of thelatter)--100.0;

product of addition of methacrylic acid to an epoxy resin based on4,4'-dihydroxy-2,2-diphenylpropane (molecular weight of the product is580 carbon units; the content of the residual epoxy groups is 0.45weight %; the acidic number is 3.6 mg KOH/g)--70.0;

triethyleneglycol dimethacrylate--20.0;

trimethylolpropane triacetate--50.0;

benzoine ethylate--10.0;

dye "Basic Blue K"--0.5;

hydroquinone--0.1.

A dry film photosensitive resist is treated by following the proceduredescribed in Example 1. The time exposure is 70 sec. A 2% aqueoussolution of sodium carbonate is used as a developer. The protectiverelief is stable in galvanic electrolytes cited in Example 1.

EXAMPLE 22

A dry film photosensitive resist is obtained and treated by followingthe procedure described in Example 21, but the content of polar oligomeris increased up to 75.0 weight parts; the content of triethyleneglycoldimethacrylate is raised up to 60.0 weight parts, and that oftrimethylolpropane triacetate is decreased to 10.0 weight parts. Theexposure time is 60 sec. The developer is similar to that described inExample 21. The dry film photosensitive resist is treated by followingthe procedure described in Example 1; the properties of thephotosensitive resist are similar to those described in Example 1.

EXAMPLE 23

A dry film photosensitive resist is obtained and treated by followingthe procedure described in Example 1, but the light-sensitive layercomprises the following components in weight parts:

copolymer of methylmethacrylate, normal butylmethacrylate,isobutylmethacrylate, and methacrylic acid (the molar ratio is45:10:10:35)--100.0;

product of addition of acrylic acid to an epoxy resin based on4,4'-dihydroxy-2,2-diphenylpropane (the molecular weight of the productis 800 carbon units; the acidic number is 4.6 mg KOH/g; the content ofthe residual epoxy groups is 0.35 weight %)--50.0;

triethyleneglycol acrylate methacrylate--30.0;

benzoine methylate--8.0;

tributylcitrate--5.0;

dye "Rhodamine 6 "--0.5;

quinhydrone--0.01.

The dry film photosensitive resist is tested by following the proceduredescribed in Example 1. The exposure time is 45 sec. A 1% aqueoussolution of sodium carbonate is used as a developer. The protectiverelief is red and stable in the same media as described in Example 1.

What is claimed is:
 1. A dry film photosensitive resist comprising aflexible laminated structure consisting of three layers: a firsttransparent polymer film transmitting UV radiation and having athickness of 5-100μ; a second light-sensitive layer having a thicknessof 5-1,000μ consisting essentially of:(a) a carboxyl-containing polymerthickener consisting essentially of a water insoluble copolymer obtainedby the polymerization of at least one carboxyl-containing monomer withat least one water insoluble monomer having a water solubility of lessthan 3 weight % at 20° C. and a pH of 7, the amount ofcarboxyl-containing monomer in the polymer ranging from 20 to 50 mol%;(b) a hydroxyl-containing polar oligomer obtained through addition of anorganic acid to at least one epoxy resin, said polar oligomer having achain length of from 300 to 3,000 carbon units, and containing 4 to 8weight % OH groups and wherein the number of residual epoxy groups inthe polar oligomer ranges from zero to 10% of the initial number ofepoxy groups; (c) a monomeric substance having a boiling point above200° C. at 760 mm Hg containing at least one fully substituted ester ofa polyatomic alcohol with carboxylic acids, at least two hydroxyl groupsof the polyatomic alcohol being substituted by residues of methacrylicand/or acrylic acid; the weight ratio of said polymer-thickener, polaroligomer, and monomeric substance in the light-sensitive layer being100:15-100:15-100 respectively; a third layer comprising a polymericfilm having a thickness of 5-100μ to form a protective layer for thelight-sensitive layer and disposed thereon, all of the three layersbeing adhesively bonded together.
 2. A dry film photosensitive resist asclaimed in claim 1, wherein the light-sensitive layer contains, as acarboxyl-containing polymer-thickener, a water insoluble copolymer of 50mol.% of styrene with 50 mol.% of monoisobutyl ester of fumaric acid. 3.A dry film photosensitive resist as claimed in claim 1, wherein thelight-sensitive layer contains, as a polar oligomer, ahydroxyl-containing compound obtained through chemical addition ofmethacrylic acid to an epoxy resin and having a molecular weight from300 to 1,000 carbon units.
 4. A dry film photosensitive resist asclaimed in claim 1, wherein the light sensitive layer contains, as apolar oligomer, a hydroxyl-containing compound obtained through chemicaladdition of acrylic acid to an epoxy resin and having a molecular weightfrom 300 to 1,000 carbon units.
 5. A dry film photosensitive resist asclaimed in claim 1, wherein the light-sensitive layer contains, as apolar oligomer, a hydroxyl-containing compound obtained through chemicaladdition of a mixture of acrylic and methacrylic acids to an epoxy resinand having a molecular weight from 300 to 1,000 carbon units.
 6. A dryfilm photosensitive resist as claimed in claim 1, wherein thelight-sensitive layer contains, as amonomeric substance,1,1,1-trimethylolpropane triacrylate.
 7. A dry film photosensitiveresist as claimed in claim 1, wherein the light-sensitive layer containsphotoinitiators of radical polymerization, the content of saidphotoinitiators being from 2 to 20% by weight of the carboxyl-containingpolymer-thickener.
 8. A dry film photosensitive resist as claimed inclaim 7, wherein the light-sensitive layer contains ketones, aromaticdiketones, multinucleous quinones as photoinitiators of radicalpolymerization.
 9. A dry film photosensitive resist as claimed in claim1, wherein the light sensitive layer contains a plasticizer in an amountof from 5 to 25% by weight of the light-sensitive layer.
 10. A dry filmphotosensitive resist as claimed in claim 9, wherein the light-sensitivelayer contains, as a plasticizer, dibutylphthalate, glycerol triacetate,or trimethylolpropane triacetate.
 11. A dry film photosensitive resistas claimed in claim 1, wherein the light-sensitive layer contains aninhibitor of radical polymerization in an amount of from 0.01 to 5.0% byweight of the carboxyl-containing polymer-thickener.
 12. A dry filmphotosensitive resist as claimed in claim 11, wherein thelight-sensitive layer contains hydroquinone or para-methoxyphenol as aninhibitor to radical polymerization.
 13. A dry film photosensitiveresist as claimed in claim 1, wherein the light-sensitive layer containsa dyeing substance in an amount of from 0.1 to 5.0% by weight of thecarboxyl-containing polymer-thickener.
 14. A dry film photosensitiveresist as claimed in claim 13, wherein the light-sensitive layercontains "Methyl violet" or "Rhodamine " as a dyeing substance.
 15. Adry film photosensitive resist as claimed in claim 1, wherein a filmfrom polyethylene terephthalate is used as the first above-mentionedlayer.
 16. A dry film photosensitive resist as claimed in claim 1,wherein a polyethylene film is used as the third above-cited layer. 17.A dry film photosensitive resist as claimed in claim 1, wherein thecarboxyl-containing monomer is an unsaturated acid selected from thegroup consisting of acrylic, methacrylic, maleic, fumaric, and itaconicacids.
 18. A dry film photosensitive resist as claimed in claim 1,wherein the carboxyl-containing monomer is monoisoamyl ester of maleicacid.
 19. A dry film photosensitive resist as claimed in claim 1,wherein the water insoluble monomer is selected from the groupconsisting of alkylmethacrylates and alkylacrylates containing from 1 to10 carbon atoms in an alcohol radical, styrene and its derivativescapable of copolymerizing which are substituted in α-position or in thearomatic ring, esters of vinyl alcohol including vinyl acetate orvinylpropionate, ethers of vinyl alcohol, including vinyl-n-butyl ether,sterically hindered monomers capable of homopolymerization includingstilbene, dienes capable of copolymerization with the formation ofsoluble copolymers including butadiene or diallyl phthalate, mixtures ofthe aforesaid monomers with water soluble monomers includingmethacrylamide, acrylamide, and mixtures thereof, wherein the amount ofwater soluble monomer in the mixture is less than or equal to 20 mol. %.20. The composition of claim 1, wherein the number of residual epoxygroups in the polar oligomer ranges from 0 to 2% of the initial numberof epoxy groups.
 21. A method for making a dry film photosensitiveresist developable with aqueous solutions of weak alkalies without theaddition of organic substances to ensure high stability in acid media,which comprises forming a flexible laminated structure consisting ofthree layers; a first transparent polymer film transmitting UV radiationand having a thickness of 5-100μ; a second light-sensitive layer havinga thickness of 5-1,000μ consisting essentially of:(a) acarboxyl-containing polymer thickener consisting essentially of a waterinsoluble copolymer obtained by the polymerization of at least onecarboxyl-containing monomer with at least one water insoluble monomerhaving a water solubility of less than 3 weight % at 20° C. and a pH ofabout 7, the amount of carboxylic-containing monomer in the polymerranging from 20 to 50 mol. %; (b) a hydroxyl-containing polar oligomerobtained through addition of an organic acid to at least one epoxyresin, said polar oligomer haing a chain length of from 300 to 3,000carbon units, and containing 4 to 8 weight % OH groups and wherein thenumber of residual epoxy groups in the polar oligomer ranges from zeroto 10% of the initial number of epoxy groups; (c) a monomeric substancehaving a boiling point above 200° C. at 760 mm Hg containing at leastone fully substituted ester of a polyatomic alcohol with carboxylicacids, at least two hydroxyl groups of the polyatomic alcohol beingsubstituted by residues of methacrylic and/or acrylic acid; the weightratio of said polymer-thickener, polar oligomer, and monomeric substancein the light-sensitive layer being 100:15-100:15-100 respectively; athird layer comprising a polymeric film having a thickness of 5-100μ toform a protective layer for the light-sensitive layer and disposedthereon, all the three layers being adhesively bonded together.
 22. Themethod of claim 21, wherein the carboxyl-containing monomer is anunsaturated acid selected from the group consisting of acrylic,methacrylic, maleic, fumaric, and itaconic acids.
 23. The method ofclaim 21, wherein the carboxyl-containing monomer is monoisoamyl esterof maleic acid.
 24. The method of claim 21, wherein the water insolublemonomer is selected from the group consisting of alkylmethacrylates andalkylacrylates containing from 1 to 10 carbon atoms in an alcoholradical, styrene and its derivatives capable of copolymerizing which aresubstituted in α-position or in the aromatic ring, esters of vinylalcohol including vinyl acetate or vinylpropionate, ethers of vinylalcohol, including vinyl-n-butyl ether, sterically hindered monomersincapable of homopolymerization including stilbene, dienes capable ofcopolymerization with the formation of soluble copolymers includingbutadiene or diallyl phthalate, mixtures of the aforesaid monomers withwater soluble monomers including methacrylamide, acrylamide, andmixtures thereof, wherein the amount of water soluble monomer in themixture is less than or equal to 20 mol. %.
 25. The method of claim 21,wherein the number of residual epoxy groups in the polar oligomer rangesfrom 0 to 2% of the initial number of epoxy groups.
 26. The method ofclaim 21, wherein the light-sensitive layer contains, as acarboxyl-containing polymer-thickener, a water insoluble copolymer of 50mol.% of styrene with 50 mol.% of monoisobutyl ester of fumaric acid.27. The method of claim 21, wherein the light-sensitive layer contains,as a polar oligomer, a hydroxyl-containing compound obtained throughchemical addition of methacrylic acid to an epoxy resin and having amolecular wieght from 300 to 1,000 carbon units.
 28. The method of claim21, wherein the light sensitive layer contains, as a polar oligomer, ahydroxy-containing compound obtained through chemical addition ofacrylic acid to an epoxy resin and having a molecular weight from 300 to1,000 carbon units.
 29. The method of claim 21, wherein thelight-sensitive layer contains, as a polar oligomer, ahydroxyl-containing compound obtained through chemical addition of amixture of acrylic and methacrylic acids to an epoxy resin and having amolecular weight from 300 to 1,000 carbon units.
 30. The method of claim21, wherein the light-sensitive layer contains, as a monomericsubstance, 1,1,1-trimethylolpropane triacrylate.
 31. The method of claim21, wherein the light-sensitive layer contains photoinitiators ofradical polymerization, the content of said photoinitiators being from 2to 20% by weight of the carboxyl-containing polymer-thickener.
 32. Themethod of claim 31, wherein the light-sensitive layer contains ketones,aromatic diketones, multinucleous quinones as photoinitiators of radicalpolymerization.
 33. The method of claim 21, wherein the light-sensitivelayer contains a plasticizer in an amount of from 5 to 25% by weight ofthe light-sensitive layer.
 34. The method of claim 33, wherein thelight-sensitive layer contains, as a plasticizer, dibutylphthalate,glycerol triacetate, or trimethylolpropane triacetate.
 35. The method ofclaim 21, wherein the light-sensitive layer contains an inhibitor ofradical polymerization in an amount of from 0.01 to 5.0% by weight ofthe carboxyl-containing polymer-thickener.
 36. The method of claim 35,wherein the light-sensitive layer contains hydroquinone orpara-methoxyphenol as an inhibitor to radical polymerization.
 37. Themethod of claim 21, wherein the light-sensitive layer contains a dyeingsubstance in an amount of from 0.1 to 5.0% by weight of thecarboxyl-containing polymer-thickener.
 38. The method of claim 37,wherein the light-sensitive layer contains "Methyl violet" or "Rhodamine" as a dyeing substance.
 39. The method of claim 21, wherein a film frompolyethylene terephthalate is used as the first abovementioned layer.40. The method of claim 21, wherein a polyethylene film is used as thethird above-cited layer.